MILAN, Italy (AP)  It was a cloudless spring afternoon, and regional government workers at the landmark Pirelli office tower were leaving for the day when a small plane smashed into the 30-story building, sending black smoke billowing into the sky.

"At the beginning I certainly thought of the September attacks in the United States," said Raffaele Taccogna, who was tending bar at the nearby Atlantic Hotel. "It really looked like the same thing."

At least five people were killed and 60 injured in Thursday's crash of a small plane en route from Switzerland to a Milan airport. Authorities said the crash, which came after the pilot made a distress call complaining of landing gear problems, appeared to be accidental.

But for many in the area, the sights and sounds evoked memories of Sept. 11  and fears that this, too, was a terrorist attack.

"It sounded like a bomb. The pavement shook like an earthquake," said a woman identifying herself only as Lucia.

Taccogna rushed out of the hotel, believing it was a terror attack.

"I heard something which seemed like a helicopter. And then I heard something like the engine of the plane which was dying out, and then I heard a terrible explosion," Taccogna said.

A reporter who was in front of the nearby central train station said the plane was in flames when it hit the building.

The plane "just went straight in," said Fabio Sunik. "Then I saw rubble falling from the building with all the smoking."

Furniture rattled in other buildings in the downtown of this busy northern Italian city known for everything from fashion to finance.

As ambulance crews and rescue workers in orange uniforms tended to the injured, a man with his shirt splattered with blood and his hand covering a gash on his head was rushed from the scene. Police cordoned off the area as people gawked at the skyscraper.

The crash left gaping holes on both sides of the slim skyscraper. Smoke and liquid poured out of the building, but firefighters quickly put out the flames. Rescuers helped bloodied men in business suits.

Debris, including twisted metal and office papers, littered the ground, and streets were closed off in the area, snarling congested rush-hour traffic in the heart of Italy's financial capital.